<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
        *,
        *::before,
        *::after {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
        }

        .row {
            background-color: skyblue;
            display: grid;
            grid-template-columns: repeat(12, 1fr);
            grid-template-rows: 50px;
            grid-auto-rows: 50px;
        }

        .row div {
            background-color: pink;
            border: 1px solid black;
        }

        .row .col-1 {
            grid-area: auto/auto/auto/span 1;
        }

        .row .col-2 {
            grid-area: auto/auto/auto/span 2;
        }

        .row .col-3 {
            grid-area: auto/auto/auto/span 3;
        }

        .row .col-4 {
            grid-area: auto/auto/auto/span 4;
        }

        .row .col-5 {
            grid-area: auto/auto/auto/span 5;
        }

        .row .col-6 {
            grid-area: auto/auto/auto/span 6;
        }

        .row .col-8 {
            grid-area: auto/auto/auto/span 8;
        }
    </style>
</head>

<body>
    <div class="row">
        <div class="col-3">1</div>
        <div class="col-5">2</div>
        <div class="col-8">3</div>
    </div>
</body>

</html>